36 • Computer Control
NEW FOCUS, Inc.
Set Power Trim
Syntax
[:SOURce]:POWer:TRIM <value>
Description
Allows you to calibrate the output power to an exter-
nal power meter. You can alter the output power by
±15% from factory settings.
Note: The laser power must be off to change the trim.
Argument
x.xx
Range: 0.85–1.15
This value is a multiplier to the photodetector signal.
Values greater than 1 will decrease the output power;
values less than 1 will result in increased power. The
value 0.85 corresponds to -0.7 dB and 1.15 corre-
sponds to +0.6 dB. To calculate a value based on a
desired dB correction, use value=10
(dB correction)/10
.
Example
The power level shown on the front panel is off by
10% when measured by an external power meter, so
you want to increase the output power by 10%:
:POW:TRIM 0.90
⇒
OK
(With the power display on the laser showing the
same power as before, the external power meter will
show that the power level has increased by 10%.)
Query Power Trim
Syntax
[:SOURce]:POWer:TRIM?
Description
Checks the trim applied the laser output power. The
trim is used to calibrate the laser to an external
power meter.
Response
“x.xx”
Example
:POW:TRIM?
⇒
1.12
(The laser has been adjusted to decrease the output
power by 12%. [10log(1.12)=0.5 dB])
64X7 rev E.fm Page 36 Tuesday, April 3, 2001 4:16 PM
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